Mercurial > hg > graal-jvmci-8
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java @ 9543:f8a5f7f7d0bd
CheckCastNode: eliminate the other way around
and replace the previous node with a more specific node regarding its type
author | Bernhard Urban <bernhard.urban@jku.at> |
---|---|
date | Fri, 03 May 2013 15:05:07 +0200 |
parents | 82b2a2c652bb |
children | 19c5a07c7843 |
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/* * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.graal.nodes.java; import com.oracle.graal.api.meta.*; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.nodes.type.*; /** * Implements a type check against a compile-time known type. */ public final class CheckCastNode extends FixedWithNextNode implements Canonicalizable, Lowerable, Node.IterableNodeType, Virtualizable { @Input private ValueNode object; private final ResolvedJavaType type; private final JavaTypeProfile profile; /** * Determines the exception thrown by this node if the check fails: {@link ClassCastException} * if false; {@link ArrayStoreException} if true. */ private final boolean forStoreCheck; /** * Creates a new CheckCast instruction. * * @param type the type being cast to * @param object the instruction producing the object */ public CheckCastNode(ResolvedJavaType type, ValueNode object, JavaTypeProfile profile, boolean forStoreCheck) { super(StampFactory.declared(type)); assert type != null; this.type = type; this.object = object; this.profile = profile; this.forStoreCheck = forStoreCheck; } public boolean isForStoreCheck() { return forStoreCheck; } @Override public void lower(LoweringTool tool, LoweringType loweringType) { tool.getRuntime().lower(this, tool); } @Override public boolean inferStamp() { if (object().objectStamp().alwaysNull() && objectStamp().nonNull()) { return false; } return updateStamp(stamp().join(object().stamp())); } @Override public ValueNode canonical(CanonicalizerTool tool) { assert object() != null : this; ResolvedJavaType objectType = object().objectStamp().type(); if (objectType != null && type.isAssignableFrom(objectType)) { // we don't have to check for null types here because they will also pass the // checkcast. return object(); } // remove checkcast if next node is a more specific checkcast if (predecessor() instanceof CheckCastNode) { CheckCastNode ccn = (CheckCastNode) predecessor(); if (ccn != null && ccn.type != null && ccn == object && ccn.forStoreCheck == forStoreCheck && ccn.type.isAssignableFrom(type)) { StructuredGraph graph = (StructuredGraph) ccn.graph(); CheckCastNode newccn = graph.add(new CheckCastNode(type, ccn.object, ccn.profile, ccn.forStoreCheck)); graph.replaceFixedWithFixed(ccn, newccn); return newccn; } } if (object().objectStamp().alwaysNull()) { return object(); } if (tool.assumptions().useOptimisticAssumptions()) { ResolvedJavaType exactType = type.findUniqueConcreteSubtype(); if (exactType != null && exactType != type) { // Propagate more precise type information to usages of the checkcast. tool.assumptions().recordConcreteSubtype(type, exactType); return graph().add(new CheckCastNode(exactType, object, profile, forStoreCheck)); } } return this; } public ValueNode object() { return object; } /** * Gets the type being cast to. */ public ResolvedJavaType type() { return type; } public JavaTypeProfile profile() { return profile; } @Override public void virtualize(VirtualizerTool tool) { State state = tool.getObjectState(object); if (state != null && state.getState() == EscapeState.Virtual) { if (type.isAssignableFrom(state.getVirtualObject().type())) { tool.replaceWithVirtual(state.getVirtualObject()); } } } }